A Fast Calculation Method of the Time–Domain Coupling Characteristics Between Buildings and Electromagnetic Pulse Based on the Electromagnetic Parameter Equivalence of Reinforced Concrete

With the development of pulse technology, reinforced concrete buildings are exposed to increasingly complex high-power electromagnetic pulse (EMP) environments, posing risks of functional degradation or destruction of indoor electronic equipment and systems. Therefore, it is imperative to assess the internal fields of buildings under EMP irradiation. The challenge lies in the multi-scale characteristics of reinforced concrete buildings, where fine grids are required for the accurate modelling of rebar, thereby consuming substantial computing resources. To address this challenge, this paper proposes a fast calculation method of the time–domain coupling characteristics between buildings and EMPs based on the electromagnetic parameter equivalence of reinforced concrete walls. The method first calculates the equivalent electromagnetic parameters from the S-parameters of the walls, which are then fitted into polynomial rational functions. Then, the auxiliary differential equation finite-difference time–domain (ADE-FDTD) method is used to analyze the time–domain coupling characteristics of reinforced concrete walls and buildings under EMP irradiation. The results show that the proposed method significantly enhances computational efficiency while maintaining high accuracy. Specifically, for a large two-story reinforced concrete building, the method achieves a 3.2-fold increase in computational speed and a 4.3-fold reduction in memory usage compared to conventional commercial software (CST Studio Suite 2022). This approach provides an effective solution for simulating the coupling characteristics between large reinforced concrete buildings and external EMPs.